\documentclass[11pt]{article}

\usepackage[active,tightpage]{preview}
\include{Qcircuit}
\xyoption{pdf}

\usepackage{rotating}

\begin{document}
\pagestyle{empty}

\begin{preview}

\def\ecBox{\push{\fbox{\raisebox{0em}[1em][0.5em]{EC}}}}
\def\dectxt{\begin{sideways}\tiny{$\begin{array}{c} \text{Ideal}\\ \text{Decoder} \end{array}$}\end{sideways}}
\def\decode{\lgate{\dectxt}}

\Qcircuit  @R=1em {
  &\ecBox \qw&\ctrl{1}&\ecBox \qw&\qw\\
  &\ecBox \qw&\targ    &\ecBox \qw&\qw
}

\end{preview}

\end{document}